Forty-one percent of Americans think Trump "should be impeached and compelled to leave the presidency," versus 53 percent who do not, according to the poll. That compares with 24 percent who supported Nixon's impeachment and 62 percent who did not in July 1973, when the Watergate scandal was escalating and about a year before Nixon resigned.

Support for Trump's impeachment is higher than Nixon's was even though the pair had roughly the same approval rating at those points in time, according to Monmouth. That may be a symptom of the more partisan environment that Trump faces, according to Patrick Murray, director of the Monmouth University Polling Institute.